Scientists have managed to produce a pregnancy in a womb transplanted into a mouse - bringing human ops a step closer.

The work by Swedish scientists using mice is the first time a uterus from one animal has been transplanted into another and resulted in a successful pregnancy.

Around 15% of all couples are infertile. Most causes can be treated by in vitro fertilisation (IVF) and sperm injection (ICSI).

This will obviously give hope to those surgeons who are interested in carrying out a similar operation in humans

Dr John Mills, British Fertility Society

However, for women who have healthy ovaries, but have had a hysterectomy or uterus problems caused by injury or congenital conditions, a transplant is their only hope of carrying a child of their own.

At the moment, they can choose IVF surrogacy, where their egg and their partner's sperm can be used, but the baby carried by another woman. Technically, this is straightforward but it may not always be suitable for couples.

Comparison

A paper published in the Journal of Endocrinology describes how scientists successfully transplanted a donor womb in a recipient mouse into which an embryo was successfully implanted.

Dr Mats Brännström of the Sahlgrenska Academy at Goteborg University in Sweden, is the researcher leading the work.

He told BBC News Online that since the paper had been published, the team had seen pregnancies in mice with donor uteruses which resulted in healthy babies.

In their original work, the team took a uterus from a donor mouse and transplanted it alongside the recipient mouse's own uterus.

This meant they could compare how both worked.

Three embryos were transferred into each uterus.

Three foetuses developed in the recipient's womb, and one in the donor womb - the first time this has happened.

That pregnancy was halted so scientists could investigate what had happened within the mouse, but subsequent pregnancies went to full-term successfully.

Suitable donors

Dr Brännström told BBC News Online: "This research is the first step towards treatment for women who have been totally infertile before.

"In the future we are aiming to achieve uterus transplantation in humans."

He said that could happen within "a couple of years".

Dr Brännström added: "Suitable donors could be either a sister after she has had her own children or a mother since the chance for a good immune and blood type match would be high.

"It would be possible to carry your own child in the same womb [donated by mother] as you
developed during your growth as a foetus."

The team has already begun tests on human tissue.

Rejection

Dr John Mills, chairman of the British Fertility Society and a consultant obstetrician and gynaecologist at Ninewells Hospital, Dundee said: "This paper has described successful pregnancies in the mouse, at least to the early pregnancy stage, and will obviously give hope to those surgeons who are interested in carrying out a similar operation in humans.

"More evidence of success in other animals will be required before it is justified to make such an attempt."

He said there was a huge difference between mice and humans which meant much more work was needed.

Dr Mills added: "We obviously have to consider the problem of rejection and, in particular, the problem of rejection and pregnancy."

He said the Swedish work, and successful pregnancies in women who had taken immunosuppressant drugs after kidney or heart transplants, showed there progress was being made on the issue of rejecting transplants.